Astigmatism is one of the most prevalent refractive errors affecting human vision. According to global ophthalmology research and statistics, approximately 30-50% of the population experiences varying degrees of astigmatism. Unlike myopia or hyperopia, which affect either near or distant vision, astigmatism impacts both, leading to blurred or distorted vision.

What Is Astigmatism?

Astigmatism is a common refractive issue caused by irregularities in the shape of the cornea (the transparent front surface of the eye) or the lens inside the eye. Unlike an ideally spherical eyeball, an astigmatic eye is more oval or football-shaped. This irregular shape prevents light from focusing properly on the retina, resulting in blurred or distorted vision at both near and far distances.

Astigmatism can occur in one or both eyes and often coexists with other refractive problems like myopia (difficulty seeing far) or hyperopia (difficulty seeing near). The severity of astigmatism varies widely, ranging from mild to severe.

What Causes Astigmatism?

The exact cause of astigmatism is not entirely understood, but several factors are associated with its development:

• Irregular Corneal Shape: The most common cause, known as corneal astigmatism, occurs when the cornea’s curvature is uneven, creating refractive errors and blurriness.
• Lens Shape Abnormalities: In rare cases, irregularities in the lens’s shape within the eye can cause lenticular astigmatism.
• Genetics: Astigmatism often runs in families, indicating a genetic predisposition.
• Eye Injuries or Surgeries: Trauma to the eye or certain surgeries can alter the cornea’s shape, leading to astigmatism.
• Keratoconus: A progressive condition where the cornea thins and becomes cone-shaped, causing severe astigmatism.

How Does Astigmatism Affect Night Vision?

The impact of astigmatism on night vision is often more pronounced because in low-light conditions, the pupil naturally dilates to accept more light. However, the larger the pupil, the more area the light passes through the irregular cornea or lens, thereby exacerbating the effects of astigmatism, thereby manifesting blurred vision, glare and halo phenomena at night; in addition, more accurate visual processing is required at night, but astigmatism causes This light dispersion cannot be corrected naturally by the eye, affecting sharpness and further reducing contrast sensitivity.

Astigmatism Lights vs. Normal Vision

One of the most notable differences between astigmatic and normal vision is how light sources appear, especially in low-light or nighttime environments.

• Blurred or Stretched Lights: People with astigmatism often see lights as blurry, stretched, or radiating streaks. For example, streetlights may appear elongated or have overlapping halos.
• Distorted Shapes: Light sources may lose their natural roundness, appearing oval or irregular instead.
• Glare and Halos: Astigmatism frequently causes distracting glare or halos around lights, particularly while driving at night.
• Reduced Contrast Sensitivity: Astigmatic individuals may struggle to perceive subtle differences in light intensity, making the visual experience less crisp than someone with normal vision.

In contrast, people with normal vision see lights as sharp, well-defined, and distortion-free. Their corneas and lenses focus light evenly onto the retina, ensuring clear and undistorted visual perception.

Treat Your Astigmatism

While astigmatism can impact daily life, proper correction and management can restore clear vision and minimize discomfort. Here are some tips:

• Wear Prescription Lenses: Use glasses or contact lenses as prescribed by your optometrist to achieve optimal vision correction.
• Optimize Lighting: Ensure adequate lighting for reading or close work to reduce eye strain.
• Regular Eye Exams: Schedule routine check-ups to monitor vision changes and update prescriptions as needed.
• Avoid Nighttime Driving: If night glare and halos are problematic, limit nighttime driving or use anti-reflective coated lenses to reduce glare.

Astigmatism is a common yet manageable vision problem that affects how light focuses on the retina, leading to blurry or distorted vision. Its impact on light perception is especially noticeable at night, where halos, glare, and shape distortion become more pronounced. Compared to the sharp, clear lights seen by those with normal vision, astigmatic vision presents unique challenges.

Fortunately, with corrective options such as glasses, contact lenses, or surgery, individuals with astigmatism can regain clear vision and enjoy a visual experience akin to normal eyesight. Early diagnosis and appropriate treatment are key to maintaining visual comfort and quality of life.